p. 133 describes the growth reactions of metal carbonates. Brian Ingemar Hernefjord (KC/EMW) wrote: > > We got lots of such growth on CBGA balls recently. After > soldering/cleaning: nada. After one week in stock: signs of growth. > After one month: unacceptable crystals. Now, being insoluble in water > and many solvents, some specialists advise you to mix an RA with > ethanol, heat this mixture and dip the part until the crystals vanish. > My question to TN is whether there is alternative methods? Some accept > PbCO3 growth as being harmless, but this is not our intention, because > loose particles are semiconducting and can create leakage current paths. > > Brian's book "Cleaning and Contamination of Electronics and Assemblies" > mention there are five groups of white residues, but, oddly enough, lead > carbonate is not included. The chemistry world of soldering residues is > so complicated, that I have to ask you for help. > > Thanks in advance > Ingemar Hernefjord > Ericsson Microwave Systems > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > -- http://www.cypenv.org Cyprus environment/energy http://www.cypenv.org/worldenv World environment/energy http://www.cypenv.org/weather Cyprus weather http://www.cypenv.org/smf/index.php Environment/energy forums http://groups.yahoo.com/group/cypnature/ Cyprus nature forum --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------